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The Government of Canada’s terminology and linguistic data bank.
SUPRAFACIAL [2 records]
Record 1 - internal organization data 2011-02-11
Record 1, English
Record 1, Subject field(s)
- Chemistry
Record 1, Main entry term, English
- disrotatory
1, record 1, English, disrotatory
correct
Record 1, Abbreviations, English
Record 1, Synonyms, English
- suprafacial 2, record 1, English, suprafacial
correct
Record 1, Textual support, English
Record number: 1, Textual support number: 1 OBS
[An electrocyclic reaction corresponds to] a molecular rearrangement that involves the formation of a [sigma]-bond between the termini of a fully conjugated linear [pi]-electron system (or a linear fragment of a [pi]-electron system) and a decrease by one in the number of [pi]-bonds, or the reverse of that process. The stereochemistry of such a process is termed ... disrotatory (or suprafacial) if one terminus rotates in a clockwise and one in the counter-clockwise sense ... 2, record 1, English, - disrotatory
Record number: 1, Textual support number: 2 OBS
The words "sigma" and "pi" must be replaced by the corresponding Greek letters. 3, record 1, English, - disrotatory
Record 1, French
Record 1, Domaine(s)
- Chimie
Record 1, Main entry term, French
- disrotatoire
1, record 1, French, disrotatoire
correct, adjective
Record 1, Abbreviations, French
Record 1, Synonyms, French
- suprafaciale 2, record 1, French, suprafaciale
correct
Record 1, Textual support, French
Record number: 1, Textual support number: 1 DEF
Se dit de mouvements en sens contraires de rotation de liaison autour d'autres liaisons que l'on doit effectuer pour ouvrir ou fermer un cycle. 2, record 1, French, - disrotatoire
Record number: 1, Textual support number: 1 OBS
[Par réaction électrocyclique, l'on entend le] réarrangement moléculaire qui comporte la formation d'une liaison-[sigma] entre les extrémités d'un système linéaire et totalement conjugué d'électrons-[pi] (ou d'un fragment linéaire d'un système-[pi] ainsi qu'une diminution d'une unité du nombre de liaisons-[pi]. L'expression désigne aussi le processus inverse. La stéréochimie d'un tel processus est dite [...] disrotatoire (ou suprafaciale) lorsque la rotation d'une des extrémités se fait dans un sens et celle de l'autre dans le sens contraire [...] 3, record 1, French, - disrotatoire
Record number: 1, Textual support number: 2 OBS
Les mots «sigma» et «pi» doivet être remplacés par les lettres grecques correspondantes. 4, record 1, French, - disrotatoire
Record 1, Spanish
Record 1, Textual support, Spanish
Record 2 - internal organization data 1996-10-11
Record 2, English
Record 2, Subject field(s)
- Chemistry
Record 2, Main entry term, English
- suprafacial
1, record 2, English, suprafacial
correct
Record 2, Abbreviations, English
Record 2, Synonyms, English
Record 2, Textual support, English
Record number: 2, Textual support number: 1 CONT
When a part of a molecule ("molecular fragment") undergoes two changes in bonding (bond-making or bond-breaking), either to a common centre or to two separate centres, external to itself, these bonding changes may be related in one of two spatially distinct ways. These are designated as "antarafacial" if opposite faces of the molecular fragment are involved, and "suprafacial" if both changes occur at the same face .... The terms antarafacial and suprafacial are, however, also employed in cases in which the essential part of the molecular fragment undergoing changes in bonding comprises two atoms linked only by a [sigma]-bond. In these cases it is convenient to refer to the phases of the local [sigma]-bonding orbital: occurrence of the two bonding changes at sites of like orbital phase is regarded as suprafacial, whereas that at two sites of opposite phase is antarafacial. 1, record 2, English, - suprafacial
Record 2, French
Record 2, Domaine(s)
- Chimie
Record 2, Main entry term, French
- suprafacial
1, record 2, French, suprafacial
correct
Record 2, Abbreviations, French
Record 2, Synonyms, French
Record 2, Textual support, French
Record number: 2, Textual support number: 1 CONT
Lorsqu'un «fragment moléculaire» (partie d'une molécule) subit deux changements dans sa façon de se lier (cette expression comprend la disparition d'une liaison ou la formation d'une liaison là où il n'en existait pas) avec un ou deux centres externes à ce fragment, ces changements de liaison peuvent être corrélés selon deux modes géométriquement distincts. Si ces changements se produisent sur des faces opposées du fragment moléculaire, on les désigne par le terme «antarafacial» et par «suprafacial» s'ils se produisent sur une même face. [...] les termes antarafacial et suprafacial sont aussi utilisés lorsque les changements de liaison concernent un fragment moléculaire comprenant deux atomes liés seulement par une liaison -[sigma]. Il est alors commode de faire référence aux phases de l'orbitale liante de symétrie locales. Ainsi, lorsque les deux changements mettent en jeu des sites orbitalaires de même signe de fonction d'onde, on utilise le qualificatif de suprafacial tandis que, dans le cas contraire, le terme antarafacial est employé. [...] 1, record 2, French, - suprafacial
Record number: 2, Textual support number: 1 OBS
À cause de contraintes informatiques, il est impossible de reproduire les lettres grecques. 2, record 2, French, - suprafacial
Record 2, Spanish
Record 2, Textual support, Spanish
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